Single operator sheet folder

ABSTRACT

A sheet-folding machine has an endless belt conveyor for moving a sheet mounted between a pair of spaced end frames. A folder bar is pivotally mounted at the output end of the conveyor belt, and a curved operator bar is mounted below the input end of the conveyor belt so as to be pivotable between start and stop positions. The folder bar is preferably operated by an electric motor drive. A return chute is positioned below the conveyor belt and is adjustably mounted between the end frames. A control system is provided which is responsive to the movement of a sheet on the conveyor belt or which is responsive to the operator bar for actuating the folder bar in the proper direction and at the proper time in order to make folds in the sheet.

United States Patent 6191 Buss et al.

[451 Aug. 14, 1973 1 SINGLE OPERATOR SHEET FOLDER [75] Inventors: Benjamin Alvin Buss; Donald C.

Buss, both of East Moline, ill.

2,969,233 1/1961 Buss 270/69 Primary Examiner-Robert W. Michell Assistant Examiner-A. Heinz Attorney-Smythe & Moore ABSTRACT A sheet-folding machine has an endless belt conveyor for moving a sheet mounted between a pair of spaced end frames. A folder bar is pivotally mounted'at the output end of the conveyor belt, and a curved operator bar is mounted below the input end of the conveyor belt so as to be pivotable between start and stop positions. The folder bar is preferably operated by an electric motor drive. A return chute is positioned below the conveyor belt and is adjustably mounted between the end frames. A control system is provided which is responsive to the movement of a sheet on the conveyor belt or which is responsive to the operator bar for actuating the folder bar in the proper direction and at the proper time in order to make folds in the sheet.

1 Claim, 12 Drawing Figures PATENTED Alli; 14 I975 SHEEI 1 BF 3 FIG INVENTORS BENJAMIN ALVIN BUSS DONAL C BUSS TTQRNEYS PAIENIED Allfi M I915 SHEET 3 0f 3 SPREADER- an sum omvs l MOTOR \J TIMER MOTOR 84 ISTFOLDTIME.

8505mm FOLD TIMER INV TO BENJAM IN A IZVI 83 INTERLOCK swncn RS NBUSS DONALD C. BUSS ORZEYS SINGLE OPERATOR SHEET FOLDER Inlarge scale laundry operations in which a large quantity of the laundry is flat work, such as sheets, blankets and pillow cases, machines have generally been used for folding the flat work after it has emerged from the ironer. Such a folding machine generally comprises an endless conveyor belt upon which the sheet is placed by an operator who must first smooth and spread the sheet so that it is introduced upon the conveyor in substantially a wrinkle-free condition. The conveyor then delivers the sheet to a finishing or ironing machine and then to a suitable folding mechanism which folds the sheet into the desired number of folds and then delivers the folded sheet to a discharge point. The successful operation of such a machine depends considerably upon the skill of two or more operators in introducing a wrinkle-free sheet to the folding mechanism and the operation of the folding mechanism at the proper times in order to carry out the desired folds. Various structures in the form of spreader devices have been devised in order to assist the operators in smoothing and spreading the sheet. The folding mechanisms vary considerably in structure, but in general, they are rather complicated in structure and are susceptible to inaccuracies in timing so that the folds in the folded sheet are not located as precisely as desired. The control of the folding mechanism is generally under the direction of the operators, and here again, the operation of the folding mechanism to produce precise folds is dependent upon the skill and experience of the operator.

.Prior folding machine generally have required two or more operators and have not returned the folded material to the operator position.

One of the objects of the present invention is to provide a sheet-folding machine having a simplified structure that is portable and a control circuit responsive to the movement of a sheet for accurately folding the sheet.

1 Another of the objects of the present invention is to provide a sheet-folding machine having an operatoractuated structure for both starting and stopping of the machine and for spreading and smoothing sheets being introduced therein.

Still another object of the present invention is to provide an improved folding structure to give greater reliability and accuracy and to prevent vibration.

In one aspect of the present invention, a portable sheet-folding machine may comprise a pair of spaced end frames between which is mounted endless conveyor belt means having an input and output end with means for driving the conveyor belt being mounted on one of said end frames. At the output end of the conveyor belt means is a pivotally mounted folder bar which is engageable with a sheet being delivered from the conveyor belt. A return chute is positioned below the'conveyor belt and slopes downwardly from its output end to below its input end. Between the end frames and below the input end of the conveyor belt means, means are provided for starting and stopping the operation of the folding machine and for spreading and smoothing a sheet as it enters'the input end of the conveyor belt. Such means may comprise a curved bar which is pivotally mounted. Means are provided responsive-to the passage of a sheet on the conveyor belt for controlling the operation of the folder bar so as to fold the sheet as it is being delivered from the output end of the conveyor belt.

In a still further aspect, electric motor operated folder blade means are used and a timing circuit which will provide good accuracy and operation is used.

Other objects, advantages and features of the present invention will become apparent from the accompanying description and drawings, which are merely exemplary.

In the drawings:'

FIG. 1 is a vertical sectional view of a sheet-folding machine according to the present invention and is taken along the line 1--1 of FIG. 2;

FIG. 2 is a front end view of the sheet-folding machine taken in the direction of the arrows 2--2 of FIG. 1;

FIG. 3 is an end elevational view of one end of the conveyor belt roll and curved operator bar;

FIG. 4 is a side elevational view of the structure shown in FIG. 3;

FIGS. 5, 6, 7, 8 and 9 are schematic views showing steps in the progressive folding of a sheet using the sheet-folding machine of the present invention;

FIG. 10 is a schematic wiring diagram showing one form of circuitry of the control circuit which can b used in the present sheet-folding machine;

FIG. 11 is a schematic view of another circuit arrangement; and

FIG. 12 is a diagrammatic view of a blade operator.

Proceeding next to the drawings wherein like refer ence symbols indicate the same parts throughout the various views, a specific embodiment of the present invention will be described in detail.

As may be seen in FIGS. 1 and 2, a sheet-folding machine according to the present invention is indicated generally at 10 and comprises'spaced end frames'll and 12 between which is mounted an endless conveyor 13 comprising a plurality of spaced endless belts or bands 14 as may be seen in FIG. 2. The belts may have a rough top. The conveyor belt means 13 has an input end 13A and an inner or delivery end 138 to the folder, the belt 13 passing over a driven roll 15 at the input end of the machine. One end of the driven roll 15 extends into a control or transmission box 16 (FIG. 2) mounted on end frame 12, and the roll is driven through a driving belt 17 (FIG. 4). I

The sheet which is to be folded is indicated at 18 and has a. leading edge 19 and trailing edge 20 as may b seen in FIG. 5.

In order to facilitate the introduction of sheet 18 to the input end of the conveyor over the driven roll 15, there may be provided a plurality of idlerrollers 21 and 22 which are spaced along the length of the driven roll as may be seen in FIG. 2. Idler rollers 21 are the first two and the last two rollers at the extreme ends of the input of the conveyor belt and are positioned immediately above the driven roll 15 as may be seen in FIG. 1. One or more rollers could be used. In the form shown, the remaining rollers 22 are positioned rearwardly of the'driven roll, as may be seen in FIG. 1,5 0 as to be in contactwith the upper'reaches of the endless .belts 14 which comprise the conveyor 13. The idler rollers 21 are mounted on arms 23 having their inner ends freely journaled upon a shaft 24 which extends between the end frames 11 and 12. Idler rollers 22 can be connected in pairs by shafts 22A in such a manner that they are articulated and can move upwardly so as to'be other than parallel with roll 15. An operator can lift up the outer rollers on one side of the machine, then stretch the sheet along the machine and insert the other edge under the rollers 21 at the other end. The machine then can be started. The insertion of the sheet by a single operation is described in more detail in copending U.S. application Ser. No. 93,967, filed Dec. 1, 19.70.

Detachably mounted between the end frames 11 and 12 and positioned below conveyor 13 is a return chute or slide 26 along which the folded sheets slide in the direction of the arrow 27 to be retrieved by the operator at the discharge end of the slide indicated at 28. The slide may be supported along its length by the transversely extending rods 29 and 30 which in turn are supported between the machine and frames.

At the folder delivery end 13B of the conveyor is a sheet-folding mechanism indicated generally at 31 and comprising a folder bar 32 which extends along the width of the conveyor 13 and is supported upon arms 33 which are pivotably mounted at 34. A link 35 connects each arm 33 to a driving arm 36 actuated by a motor 37. A motor can be used at both sides of the machine, the motors being reversible so as to operate in two directions, and it is this movement of the motor which imparts a forward and reverse movement to the folder bar 32.

The bar 32 has a plurality of tabs 38 spaced along its length and the bar is engageable with a cushioned clamping plate 39 when the bar is moved to the clamping position indicated by the dash lines 40 (FIG. 1). The clamping plate 39 is covered by an angle member 41 for protection.

A permanent split capacitor reversing gear head type motor can be used which will eliminate many of the problems encountered with solenoids. A solenoid may require frequent service because of its high impact, high inertia characteristics in the size needed to operate a folding blade.

A proper size capacitor and motor will provide 125 to I50 percent of the starting torque needed. By slightly over-motoring, the full load speed of such a motor will be nearly synchronous over a relatively wide range of torque, e.g., one-half or more of rated torque. If some assistance is provided by use of a resilient positive stop in both directions for starting and reverse direction operation of the blade, a remarkably constant speed of the folding blade will be obtained.

It also is preferable to arrange the levers and blade operators as shown in FIG. 12 wherein blade arm 33A is fastened by link 35A to motor operator arm 36A. By such an arrangement where the arm 36A is moved through an angle of approximately 120, advantageous starting and holding force is obtained.

It is desirable to arrange the system so that the velocity of the blade is at a velocity exactly, or as near as possible, to that of the sheet to be folded, for example, I35 feet per minute.

The components of the present folding machine are detachably mounted between the end frames 1 l and 12 which may be particle board panels mounted on legs 11a and 120 comprising metal angle members. This structure permits ready assembly and disassembly of the apparatus so that the apparatus may be shipped in various knock-down forms. For example, the legs only can be made disassemblable from the remainder of the structure which will facilitate shipment.

The starting of the machine can be controlled by a curved operator bar 45 mounted immediately below the input end 13A of the conveyor. The operator bar 45 is curved outwardly, as may be seen in FIGS. I and 2, and at its ends is pivotably connected by short shafts 46 (FIG. 3) to the end frames. The operator bar is movable between start and stop positions and in these positions actuates switches 47 and 48 (FIG. 4) which control the operation of the drive for the conveyor belt. The operator rod may be readily lifted into the start position with one hand by the operator and is biased in this position by means of a spring 49.

In one form of the invention, in order to fold a sheet with the folding machine of the present invention, the operator places the leading edge of the sheet or blanket under the holding rollers 21 and 22 at the input end 13A of the conveyor 13 and raises the curved operator bar 45 to start the folder run motor.

In one form, the leading edge of the sheet can actuate a leading edge switch 62 positioned just before the output end of the conveyor to start a first timer. The first timer will time out to energize a load swtich which applies power to reverse the fold motor and to start a second timer. The second timer will time out and remove power from the reverse fold motor, apply power to the forward fold motor and to a third timer. The third timer times out and energizes an unlatching circuit to remove all power to close down the cycle. The latched circuit applies power to the timers when given a momentary a.c. pulse and also removes all power at the end of the cycle. The first timer is continuously adjustable over the range needed to give a satisfactory first fold for all lengths of flat material. The second timer is also continuously adjustable over the range required to give a satisfactory second fold for all lengths of material. The third is a fixed-time timer that runs the conveyor drive motor long enough to clear the material from the rollers at the output end of the conveyor after the second fold. All of the timers may incorporate a timing network voltage level stabilization circuit to provide repeat timing accuracy.

The control circuit which operates the foregoing form of folding machine in the sequence as described above is shown schematically in FIG. 10. The several components of the control circuit will be described with reference to sequence of operation of this circuit as applied to the folding machine.

To begin operation of the control circuit, the operator actuates an on-off switch 50 (FIG. 10) located in lines L -L leading to a source of electrical energy so that this switch is in the on position. At the same time, a length selector switch indicated generally at 51 is actuated to one of five pre-set length selections as indicated by lines 52, 53, 54, 55 and 56. For the present example, it is assumed that the selector is actuated for length 52.

The sheet 18 is shaken out by the operator, and the leading end 19 is inserted between drive roll 15 and the idler rollers 21 and 22. The entire sheet is pulled taut parallel to drive roll 15 until the entire edge is positioned between the drive roll and the idler roller.

The operator then pulls operator bar 45 into its upward position to close a conveyor drive motor start switch 57. In this position, the operator bar also can be used to spread and smooth out the sheet as the sheet is being fed into the conveyor.

Closing of the start switch 57 energizes relay CR-l to close its contacts with one set of the relay contacts closing to energize the conveyor drive motor 58. This drive motor is connected by means of the drive belt 17 and a gear or pulley 59 to the drive roll as may be seen in FIGS. 3 and 4. Another set of relay CR-l contacts closes to complete a holding circuit to a coil of the relay CR-l. This holding circuit includes an emergency stop switch 60, a drive motor stop switch 61, CR-l contacts and the coil of the relay.

With drive motor 58 energized, the sheet 18 will now be conveyed toward a measuring switch 62 as seen in FIG. 5 located just forward of the delivery end of conveyor 13 as shown in FIG. 1.

The leading edge 19 of the sheet actuates switch 62' to complete the circuit between line L and line 63 to start the folding timer motor 65. After approximately a 5 rotation of a cam (not shown) attached to the timer motor 65, a switch 64 closes which is the timed end of the cycle. This switch is used to insure that the trailing edge of the sheet is delivered from the pinch rolls at the delivery end of the conveyor before the cycle is closed.

At the same time that the timer motor 65 is energized, the two folding motors 37, each mounted on an end frame of the machine, are energized in the forward direction to insure that the folding blade is in its forward position for the beginning of the fold cycle (FIG. 6). The circuit is from line L to line 63, line 52 and line 66 to the fold motors 37.

When one-fourth of the sheet length 18 has passed the pinch point of the discharge rolls of conveyor 13, a timer operated cam switch in line 52 will open a circuit between line 52 and line 66 and close the circuit between line 52 and lines 67. This action will move the fold motors 37 in the reverse direction to clamp the sheet against the fold-back stop cushions located on the clamping plate 39 (FIG. 7).

When three-fourths of the length of sheet 18 has passed the pinch point of the conveyor discharge roll, the timer operated cam in line 52 will cause a switch to open line 52 from line 67 and close line 52 to line 66. This action will move the folding blade motors 37 forward to force the sheet into the intersection of the pinch rolls (FIG. 8). The sheet is then pulled through thefolding rolls and then delivered down chute 26 folded in quarters (FIG. 9).

The measuring switch 62 is released as trailing edge 20 of sheet 18 passes over it, and the timer switch 64 continues the operation of timer motor 65. Shortly after the sheet is delivered in its folded condition to the front of the folder, timer 61 opens and turns off the conveyor drive motor by opening the holding circuit to relay CR-l. Shortly after the drive motor circuit is opened, the switch 61 will reclose.

Shortly after the motor stop switch 61 recloses, timer stop switch 64 will open and the timer motor 65 will stop. Power will also be removed from the folding blade motors 37 on the opening of the timer stop switch 64. This completes the cycle of operation and the folder is now ready for the next sheet.

An example of a preferred circuit is shown in FIG. 11 wherein power lines L,, L, furnish power to the timer and folder control circuit. When the spreader bar 45 is raised, switch 80 is closed which will start drive motor 81 and also timer motor 82. The timer motor has one cam connected thereto (not shown) and timer motor interlock switch 83. At the end, for example, of 6 seconds, the timer motor switch interlock 83 will open and stop the machine, the time being chosen so that it is longer than that required to complete the folding of the. sheet. Electronic timers 84, are started, timer 84 being referred to as the first fold timer and timer 85 being referred to as the center fold timer. A timer which can be used is one referred to as a Hybrid Solid State Timer, such as sold by Tempo Instrument Co., Plainview, Long island, N.Y., Model 333-142.. Such a timer has solid state timing circuit rneans which operates an electro-mechanical switch means. Other solid state timers, of course, can be employed.

The first fold timer 84 can be set to time out, for example, in 2 seconds, and the second fold timer 85 in 4 seconds. The sheet travels along the conveyor which, for example, can be about 24 inches so as to take about I second to travel to the folding rolls when the conveyor belt moves at a speed of 2 feet per second. The sheet then goes over the roll and when one-fourth of thelength of the sheet has passed thereover, timer 84- completes its timing and closes normally open switch 86. Switch 86 can be an electro-mechanical relay. The

fold motors 87, 88, at either end of the machine, will.

move the fold bar or blade back and clamp the first quarter length of the sheet against the back plate 39- (FIG. 7). The bar stays in the clamping position until another few seconds has lapsed, the loop 89 (FIG. 7) being formed during this period. Then the center fold timer electro-mechanical relay will open normally closed switch contacts 90 and close normally opencon' tacts 9-1; that is, the center fold timer takes control from the first timer 82 and causes motors 87, 88 to re verse to move the folder bar forward so as to move the sheet between the pinch rolls (FIG. 8). Capacitor 92 is the capacitor for the permanent split capacitor motors 87, 88 which are three lead motors as known in mean.

Thus, it can be seen that the interval can be initiated by the starting of .themachine, the sheet traveling down the conveyor and the timer starting to operate. As the sheet passes the folding bar and travels one-fourth of its length therebeyond, the first timer causes the bar to move back and clamp the sheet. Further movement "of the sheet results in a loop being formed, the second or center fold timer determining the length of the loop. The loop forms the two middle quarters of the sheet and if measured accurately, the trailing quarter will be' correct or can be adjusted by changing the loop. The second timer then causes the folding blade to reverse and move the sheet between the folding rolls (FIG. 8). From there, the sheet will slide in folded condition down chute 26 to the front of the machine.

Timing fingers can be used adjacent the input end of the conveyor instead of the curved bar being used to tion including a pair of spaced end frames, endless conveyor belt means mounted between said frames having an input end adjacent the front of said machine anda' delivery end adjacent the rear of said machine wherein sheets to be folded are inserted by the operator at the front of said machine, means on one of said end frames for driving said conveyor belt means, a folder bar pivotably mounted at the delivery end of said conveyor belt means and engageable with a sheet being delivered from the delivery end, a return chute below said conveyor belt means and sloping downwardly from said delivery end toward and below said input end and adjacent thereto for feeding folded sheets from the delivery end of said conveyor back to the operator at the front of said machine, and means between said end frames and below said input end of the conveyor belt means for starting and stopping the operation of the folding and smooth a sheet entering the input end.

. UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No; 3,752,470 Dated August 14, 1973 Inventor(s) Benjamin Alvin Buss It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Patent Front Page [56] "10/1966" should be -l0/l960--. Column 3, line 6, "operation" should be -o'perator-; Column 3, line 15, "and" should be end.

Column 4, line 22, "swtich" should be switch-.

Column 6, lines 8 and 9, Hybrid Solid State Timer, should be in quotation marks Signed and sealed this 23rd day of April l97L (SEAL) Attest:

Emmm M .FLETCIIER JR o MARSHALL DANN Attesting fficer Commissioner of Patents ORM P -1 USCOMM-DC 60876-P69 fi I] S GOVERNMENT PRINTING OFFICE l9, 0-356-334. 

1. In a single operator controllable laundry sheet-folding machine having a front and a rear, the combination including a pair of spaced end frames, endless conveyor belt means mounted between said frames having an input end adjacent the front of said machine and a delivery end adjacent the rear of said machine wherein sheets to be folded are inserted by the operator at the front of said machine, means on one of said end frames for driving said conveyor belt means, a folder bar pivotably mounted at the delivery end of said conveyor belt means and engageable with a sheet being delivered from the delivery end, a return chute below said conveyor belt means and sloping downwardly from said delivery end toward and below said input end and adjacent thereto for feeding folded sheets from the delivery end of said conveyor back to the operator at the front of said machine, and means between said end frames and below said input end of the conveyor belt means for starting and stopping the operation of the folding machine and for spreading and smoothing a sheet as it enters the input end of the conveyor belt means, said means for starting and stopping operation of the folding means having starting and stopping operating positions and comprising a curved operator bar pivotably mounted for movement between said starting and stopping positions, said operator bar being curved outwardly with respect to said folding machine, said operating bar extending outwardly of a vertical line from the input end of said conveyor belt means to spread out and smooth a sheet entering the input end. 